docs: def to_python(self, value):
          """
          Convert a string from the database to a Python value.
          """
          if value == "":
              return None
  
          try:
              if isinstance(value, six.string_types):
                  return self.deserializer(value)
              elif isinstance(value, bytes):
                  return self.deserializer(value.decode('utf8'))
          except ValueError:
              pass
          return value